FIG. 7 shows a portion of prior art coolant control valve 200. Valve 200 includes: housing 202; end stop 204 fixedly connected to housing 202; and rotary valve 206 with end stop 208. End stop 204 is made of a rigid, non-flexible material, for example plastic used to construct housing 202. Valve 206 includes axis of rotation AR. Coolant control valves such as valve 200 are used in internal combustion engines and typically include at least one actuator (not shown) and one or more rotary valves, such as valve 206. End stops 204 and 208 are provided on housing 202 and rotary valve 206, respectively, to limit the rotation travel angle of rotary valve 206. Also, end stops 204 and 208 are used for calibrating rotary valve 206.
To reduce cost and weight of valve 200, plastics are typically used for end stop 204 and/or end stop 208. However, a plastic end stop 204 or 208 tends to break due to fatigue after extended use, or from excessive loads, for example associated with rotation of valve 206. Valve 200 does not function properly without intact end stops 204 and 208. For example, when one or both of end stops 204 and 208 break, valve 206 can rotate past the circumferential position of end stop 204, nullifying calibration and control schemes for valve 206. The problem of end stop failure is exacerbated by the need to reduce the circumferential thickness of end stops 204 and/or 208 to maximize rotary valve travel, thereby further reducing the strength and durability of the end stops.